Do you run your place, your hotel, your store, your company with one manager? If not, could you? If you don't think so, list all the reasons why and start chipping away at those obstacles...immediately. Some that come to mind...

Reporting

Legal

Financial- salaried people reduce hourly rate of pay (they work tons of hours)

Skills

Oversight- Measuring the performance of others

Scheduling

Management

Guest Satisfaction

You may never get to the one manager state, but you will improve your organization if you scrutinize your status quo...guaranteed.

Of course, the other way to look at this...run your place with only managers (or, those with the skills to fit into that category as you currently have it defined). Who could be promoted today, tomorrow, in a week or month?